Corybas trilobus COMMON NAME Spider Orchid SYNONYMS Nematoceras trilobum Hook.f. FAMILY Orchidaceae AUTHORITY Corybas trilobus (Hook.f.) Rchb.f. FLORA CATEGORY Vascular – Native ENDEMIC TAXON Yes ENDEMIC GENUS Mt Te Moehau, September. Photographer: John No Smith-Dodsworth ENDEMIC FAMILY No STRUCTURAL CLASS Orchids NVS CODE NEMTRI CHROMOSOME NUMBER 2n = 36, 72 Mt Te Moehau, September. Photographer: John Smith-Dodsworth CURRENT CONSERVATION STATUS 2012 | Not Threatened PREVIOUS CONSERVATION STATUSES 2009 | Not Threatened 2004 | Not Threatened DISTRIBUTION Endemic. North, South, Stewart Islands HABITAT Coastal to subalpine (up to 1200 m a.s.l.). Probably the most widely ranging of all the New Zealand species, occupying a diverse array of habitats from coastal dune forest and scrub to subalpine shrublands and mires. More than one species is involved (see under similar species), and any clear habitat distinction at this stage is impractical. FEATURES Terrestrial, tuberous, glabrous, extremely variable winter to summer-green herb forming dense colonies of many plants through vegetative extension. Plant at flowering 20-50 mm tall, flower usually set above leaf but sometimes beneath. Leaf distinctly petiolate; petiole 10-24 mm long; lamina membranous 10-30 mm diameter, dark green to green, reniform to orbicular, usually wider than long, and mostly bearing a distinct median apiculate lobe, base broadly cordate. Floral bract rarely as long as ovary, linear-lanceolate to lanceolate. Peduncle short to long. Ovary erect, creamy yellow to yellow-green, ribbed. Dorsal sepal short, spathulate, obtuse and concave, rounded to cucullate at broad tip, arched over top of labellum, mostly green with purple flecks, sometimes translucent yellow- green with purple flecks or completely white; lateral sepals long, filiform, greatly exceeding labellum, usually basally red fading through pink to translucent white or completely white. Petals similar to lateral sepals in colour and shape, but usually much shorter. Labellum colour variable, sometimes deep crimson or maroon, otherwise reddish grading through to translucent with purple or even greenish flecks or stripes,occasionally completely white, auriculate at base, lamina very abruptly deflexed, broad and rounded, margin entire, usually incurled except at the lower edge, inner surface retrorsely papillose. Seedling peduncle up to 200 mm tall. SIMILAR TAXA Corybas trilobus is a species aggregate that requires critical taxonomic investigation using a wide range of modern techniques. The aggregate is unified by, and distinguished from all other species by the more or less trilobed leaf (in some more distinctly so than in others). Chromosome counts indicate two cytotypes a diploid and a tetraploid, and there is some correlation between these cytoraces and their morphology. The relationship of the subantarctic and Chatham Islands forms to the newly described Macquarie Island endemic C. sulcatus need careful evaluation. The above description encompasses several commonly encountered forms. Recently Lehnebach et al. (2016) segregated from C. trilobus five new species, even so C. trilobus remains variable and probably requires further taxonomic revision. FLOWERING July - December FLOWER COLOURS Green, Red/Pink FRUITING August - April PROPAGATION TECHNIQUE Difficult - should not be removed from the wild. Can be grown in basic orchid mix consists of 2 parts medium coarse sand, ideally clean river sand; 2 parts soil, humus or leaf-mould; 1 part weathered sawdust or rotting wood; 1 part granulated bark. Many Corybas thrive if more leaf-mould is added, and the plants grown in 50-70% shade, in the cooler, darker end of the shade-house, in pots kept moist throughout the growing period. ETYMOLOGY corybas: Helmet flower WHERE TO BUY Not commercially available TAXANOMIC NOTES Considerable research is underway to investigate the validity of the segregate genera split from Corybas R.Br. by Jones et al. (2002). Whilst much of that work has yet to be published, on advice from Australian Orchidologists Peter Weston and Stephen Hopper (pers. comm., July 2011, November 2014), all of the segregate genera recognised for New Zealand by Jones et al. (2002) are returned to Corybas. Lehnebach (2016) has made three combinations for those Nematoceras lacking valid names in Corybas. This action now enables the full transfer of Nematoceras back to Corybas. However, as of writing, a formal publication rejecting the segregation of Corybas by Jones et al. (2002) has yet to be published. Lehnebach cites an unpublished PhD (Lyon 2014) that indicates this move is imminent. Recently Lehnebach et al. (2016) segregated five new species from Corybas trilobus. However, in the process they did not recircumscribe C. trilobus leaving it unclear which of the remaining variants currently accepted within that name match the type. Until this is done a clear understanding of Corybas trilobus sensu. stricto is still unavailable. In October 2016 an article in Trilepidea (issue 155, p. 9) by Jeremy Rolfe provides useful characteristics in Corybas trilobus agg. ATTRIBUTION Fact Sheet prepared for NZPCN by P.J. de Lange 14 April 2007. Description adapted from Moore and Edgar (1970). REFERENCES AND FURTHER READING Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Government Printer, Wellington. Jones, D.L.; Clements, M.A.; Sharma, I.K.; Mackenzie, A.M.; Molloy, B.P.J. 2002: Nomenclatural notes arising from studies into the Tribe Diurideae (Orchidaceae). The Orchadian 13: 437-468. Lehnebach, C. 2016: New combinations and a replacement name for three New Zealand spider orchids (Corybas). The New Zealand Native Orchid Journal 139. 4-5. Lehnebach, C.A., Zeller, A.J.; Frericks, J.; Ritchie, P. 2016: Five new species of Corybas (Diurideae, Orchidaceae) endemic to New Zealand and phylogeny of the Nematoceras clade. Phytotaxa 270:1-24. Lyon, S. P. 2014: Molecular systematics, biogeography, and mycorrhizal associations in the Acianthinae (Orchidaceae), with a focus on the genus Corybas. PhD Thesis, University of Wisconsin-Madison. USA. CITATION Please cite as: de Lange, P.J. (Year at time of access): Corybas trilobus Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/corybas-trilobus/ (Date website was queried) MORE INFORMATION https://www.nzpcn.org.nz/flora/species/corybas-trilobus/.